The disclosed invention relates to the field of filter systems for fluid handling devices, and in particular to integral air handling techniques designed into computer equipment for maintaining temperature control of delicate electronic components, and even more particularly, to optical information storage and retrieval devices.
The use of filter systems and in particular air filter systems in such computer equipment has become common because of the detrimental effects of accumulative contamination over prolonged periods of operation.
The prior art has relied heavily upon the thermal chimney effect to move cooler air into high temperature areas. In the prior art, a wide range of means have been developed to reduce the accumulated contamination which results from the continual circulation of air throughout the device. The sensitivity to contamination is most critical in equipment which contains assemblies and sub-assemblies which must be sealed and protected against the hostile environment outside the delicately clean manufacturing facilities where they are assembled.
The prior art has addressed these problems in part by placing filter barriers in the air flow path of the major contributing air streams. Reduction in accumulated contamination is achieved by periodically removing the old filters and replacing them with new ones. While installing new filters addresses the accumulated contamination problem and allows sufficient air flow through the system, removing the old filter from its installed position usually releases a relatively substantial quantity of residual contamination which remains in the filter chamber of the air filter system. Also, the new filter itself usually contains contaminates which are able to enter the filter system.
What is needed, therefore, is an efficient air filtering system that not only removes contaminates from the circulating air, but which also prevents contamination of the system during filter replacement.